Related Clues:

• Like urban populations
• Hard to see through
• Completely full
• Far from 22-Down
• Overgrown
• Hard to see through, as fog
• Stuffed to the limit
• A little on the slow side
• Not sparse
• Not Mensa material
• Compacted
• Filled to capacity
• Like thickets
• Not the sharpest pencil in the box
• Not very sharp